1. Field of the Invention
The invention relates generally to surgical procedures for treating cataract. More particularly, it relates to a treatment of cataract in combination with an ab interno procedure for maintaining the intraocular pressure by permitting intraocular liquid to flow out of an anterior chamber of the eye through a surgically stented pathway.
2. Description of the Related Art
As is well known in the art, a human eye is a specialized sensory organ capable of light reception and is able to receive visual images. Aqueous humor is a transparent liquid that fills the region between the cornea, at the front of the eye, and the lens. A trabecular meshwork, located in an anterior chamber angle formed between the iris and the cornea, serves as a drainage channel for intraocular liquid from the anterior chamber, which maintains a balanced pressure within the anterior chamber of the eye.
Artificial intraocular lenses are widely used to replace the human crystalline lens of the eye. The human crystalline lens is a living transparent structure composed primarily of protein having a thickness of about five millimeters and a diameter of about nine millimeters. The lens is suspended behind the iris by zonula fibers that connect the lens to the ciliary body. A lens capsule surrounds the lens; the front portion of the capsule is generally referred to as the anterior capsule and the back portion is generally referred to as the posterior capsule.
The term “cataract” refers to the opacity of the lens of the eye. There are a variety of types of cataracts and for most cataracts, surgical intervention is required to remove and replace the lens with an artificial intraocular lens.
There are a number of procedures and devices that have been developed for the removal of the natural lens followed by the insertion of an artificial lens. The extraction procedure can generally be categorized as intracapsular (i.e., where the lens is removed together with the lens capsule) or extracapsular (such as where a portion of the anterior capsule is circularly removed (capsulorhexis) and the posterior capsule is left intact).
Presently, phacoemulsification is a widely used method for the removal of diseased or damaged natural lens tissue. The phacoemulsification process generally employs a small incision typically of about 2 millimeters (mm) to about 4 mm in length through the cornea and a probe is used to ultrasonically break apart and remove the crystalline lens through the capsulorhexis.